I don't believe that is actually true. If you look at the information that is out there for people with thyroid cancer (who have to be on low iodine diets) you can find lists of products that use non-iodized salt (and there really are not that many - one notable exception is Lays). So many of the common big brands, tomato ketchup, soups, cakes, bread etc contain iodized salt (most of the information is by people who have called the companies to specifically ask them, and is shared because these people cannot medically ingest iodine) Catering supply stores / whole sale outlets, places where small processed food producers buy their ingredients from, sell iodized and non iodized salt, which last time I looked cost the same, thus when I buy a jar of pasta sauce from the farmer's market, as I did yesterday, that salt is quite probably iodized (as something like 70% of manufactured table salt - which is what they buy in wholesale form from the catering supply store) is iodized. Kosher and sea salts tend to be more expensive, so are not the first choice for a use where the taste difference would be negligible. 'Processed foods' covered everything from major producers (say, Kraft for example) right down to the farmer who sells pasta sauce at the farmers market - both have vastly different resources, methods etc so grouping 'processed' to include both means things cannot necessarily be same for both. I can't recall the last time I ate KD, but I have eaten non-homemade (but made by small producers) pasta sauce at least 3 times in the last week.

I think people are more salt aware, as people are becoming more aware of hypertension etc. Certainly I see less salt added at the table than I saw 10 or 20 years ago (I was very conscious of it because as a family we really didn't have much salt - all home cooked foods, and no salt shakers on the table, so I was very aware of other people adding salt to everything, and finding pre-made foods very salty tasting) and I know far more people who use salt like Maldon rather than cheaper processed (and more often than not, iodized) table salt in their cooking (both for taste, and some food snobbery) now than in previous years. Those could certainly contribute to iodine levels.

But one factor that doesn't seem to be addressed in that article is that fact iodine levels in meat, vegetables and milk are far lower these days than say, 20 or 50 years ago (due in part to soil levels of iodine being a lot lower) thus the non-salt sources of iodine are decreasing. Another factor is that uses of salt that existed say 50 years ago are almost obsolete, or replaced by other processes (who cures meat with just salt anymore - very few, because nitrates an nitrites leave a product that appeals more to consumers (nice pink colour) and improve food safety). Things that were once almost always preserved in brine (which more often than not is artificial, not brine from the sea) are now offered in water packed containers, or other methods (canned, vaccum packed, etc) that taste better and as people are increasingly aware of the dangers of excess sodium. When was the last time you ate brined carrots, for example?

I haven't added iodized salt to food at home for the last 5 years. I don't eat fish, seaweed or seafood, never eat meat, and very rarely eat yogurt (maybe once or twice a month) and never drink milk. So it stands to reason that I must be getting my iodine from elsewhere (and having had thyroid function tests recently I know my levels are ok), which leaves processed foods like bread, sauces, etc. as the only real source (I do eat eggs, but at around 10 micrograms each, they certainly don't make up my RDA).